A thermostat that learns? Three months with the Nest

It has been close to a year since the Nest "learning" thermostat was introduced to the public, bringing us one step closer to that elusive home of the future. Founded by the former senior VP of Apple's iPod division, Tony Fadell, along with his partner Matt Rogers, Nest Labs set out to create what is essentially the iPod of the thermostat world. The round, user-friendly device was initially met with excellent reviews, but were these based in reality or were they the result of some Apple-like hype?

I like to think of myself as somewhat of a thermostat nerd. (Listen, it doesn't sound very exciting because it's not, but I like them). I am fascinated by thermostats and their usability, but I also don't like to spend too much money on them—unless the extra cost is worth it. Friends and Twitter followers have long asked me to evaluate higher-end thermostats, and I'm always examining the thermostats at other people's houses. So when I finally had the opportunity to install a Nest, I jumped at it.

Now that I've been using the Nest for several months, I have a pretty good feel for its strengths and weaknesses—at least compared to what is typically available on the market. Is the Nest really worth the $250 it costs to obtain one, just so you can have a fancier way of turning the temperature up and down? I think so—especially if you're the "convenience oriented" type (that's PC for "lazy").

What's so great about the Nest anyway?

General usability

The usability of the device as "just" a thermostat is extremely straightforward, and it's the first thing you deal with after installation. Overall, it's pretty good—as you've likely already seen, the thermostat itself is a round wheel, similar to the original iPod's moving click wheel, but in thermostat form. The device has a backlit screen that comes on when you mess with it, or whenever you pass by it (if you have that setting turned on). I like to have it light up when I walk by, because it allows me to see the current setting at an easy glance as I'm on my way to the fridge or the living room.

The background color of the Nest turns blue when the air conditioning is running, and an orangey reddish color when the heat is running. When nothing is running at all, the background is black and the text is white. Just walking up to it and turning the dial will wake it up and allow you to turn the temperature up or down. If that's all you ever wanted to do with your thermostat, then that's really all you need to know.

More importantly, the device can connect to your WiFi network, which lets it perform a number of valuable functions. For one, it can update its own software over WiFi, allowing the company to issue bug fixes and even add features (if they should feel so inclined). Since the Nest's original release in October of 2011, there have been 10 software updates seeded wirelessly to users' Nests, most of which were released in May of 2012.

That in itself is a handy feature, but the WiFi functionality serves another purposes to us lazy geeks: the ability to see stats and make changes to our settings remotely. Nest comes with a Web app, as well as an app for iPhone, iPad, and Android—the functionality of which I'll get to in another section of this review.

But the Nest's interface can do a lot more. In addition to turning the thermostat, you can also "click" it by pressing down on it; this brings up a plethora of other features that you can scroll and click through. If you want to set yourself to "away" (more detail on this later), you can do so by clicking once and turning to the away setting. You can also enter your address when you first set up the device so it can bring in the local weather. This is useful for its energy statistics, because it can tell you whether the day's weather affected your thermostat use. You can also set up your account there and view/change the Nest's learned schedule.

Learning features

In fact, the Nest's headline feature is its capability to learn. The device learns what you like, when you like it—there is no schedule to program, only a schedule to live. If you want the thermostat set to a certain temperature when you get home from work, set it that way for several days and the Nest will eventually figure it out. Do you like the temperature to be at 75°F at 6pm on Monday through Thursday, but 73°F at 3pm on Fridays and 80°F at 4pm on Saturdays? The Nest will figure that out too, as long as you give it a few data points to work from.

I found that it generally takes about a week or so to train a Nest to conform to your schedule. That's not too bad, especially if you consider the trade-off in the time it typically takes you to figure out how to program—and reprogram, in the case of a schedule change—your older thermostat. There is no reprogramming involved with the Nest. If your schedule or preferences change, you can just start training it to your new schedule and it'll be there in a few days. But if you need a one-off temperature change—say you're home "sick" for the day but you're really playing the new Call of Duty—it won't throw off your schedule. Individual temperature changes won't force the whole schedule to change unless you make that change consistently for several days in some kind of pattern. And even then, it will eventually switch back if you somehow end up switching back to your old schedule.

Other cool features

The Nest learns things besides your schedule, too. One of my favorite features is its time estimates for when it will reach the temperature that you've requested. Nest's materials state over and over that you can't get to a cooler (or warmer, depending on the season) temperature by setting it to extremes, so don't do it—instead, it tries to tell you that it will reach 73°F in, say, 25 minutes. It takes several weeks for the Nest to learn how fast it takes to heat or cool your place to the desired temperature, but I have found that after a few weeks, the time estimates are extremely accurate. I have set the temperature and taken note of the time estimate many times over the past several months, while also setting a timer on my phone, and found the times to be almost exactly on point, adding a certain comforting layer of information to your temperature choices. (Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen.)

In fact, setting your Nest to extreme temperatures isn't just useless—it's actually a bad idea. Since the Nest learns from the temperatures that you set, it could learn that you actually want it to be 55°F all the time (when you actually want it to be 70°). Luckily, the Nest seems to discourage this behavior—perhaps even indirectly—because of the time estimates; when someone sets the temperature to significantly lower than it is currently, they may not feel very satisfied once the Nest tells them it'll take 5+ hours to get there, forcing them to reconsider their temperature choices.

There's also the away and auto-away modes. While the Nest allows you the ability to manually set yourself to away—say if you're going on vacation or even just going away for the weekend—it can also detect when there hasn't been any activity nearby and will automatically determine that you're not home. The Nest has a motion detector that allows it to do this, and you can set the maximum and minimum temperatures you'd like to maintain through either the Nest's website or on the Nest itself.

For example, I have my maximum temperature set to 80°F (I have cats, so I don't want them to boil to death) and the minimum set to 60°F; this temperature range applies to both regular "away" mode and auto-away. If the Nest hasn't seen me in a few hours, it will just set itself to auto-away and won't turn on again until 1) it sees me again, 2) it hits one of my preset thresholds, or 3) I manually change it remotely. Upon viewing your energy history (again, more on this later), you can definitely see where the benefits of auto-away kick in. The Nest tells you which days were affected by which factors, and being set to auto-away (so the thermostat saves its energy) appears often in my timeline.

My only beef with auto-away mode is when you are home, but you just don't pass by the Nest very often in the course of navigating your place. I'm often not on the same floor as my one and only thermostat, so it sets me to auto-away more often than actually needed. This can be solved by adding another Nest (as they can talk to one another and adjust themselves accordingly), but naturally, that costs another $250.

And if you live in a home with people you don't trust—kids, or your shady brother-in-law—you can lock the Nest with a PIN as well so that no one can change the temperature. You can only set the PIN on your physical device (not the website), and if you're the owner of the Nest, you don't have to worry much about losing the PIN either, as long as the account is associated with your e-mail address. You can reset it if necessary, and the process isn't any more painful than resetting your password on a website.

Finally, the Nest learns any and all adjustments you make. Whether you're making adjustments from the website a thousand miles away, from your iPhone in bed, or while standing right in front of it, you can train it to whatever patterns you have in your normal life.

Jacqui Cheng
Jacqui is an Editor at Large at Ars Technica, where she has spent the last eight years writing about Apple culture, gadgets, social networking, privacy, and more. Emailjacqui@arstechnica.com//Twitter@eJacqui

223 Reader Comments

This really interests me though I have only a simple ducted heating system (two-wire control). So far I have found that it can display temperatures in degrees Celsius for use in most of the rest of the world, and if I can get around the purchase/shipping problem it should work fine, I can't think of why they would bother to do a Pandora-style geographical IP restriction on the internet services...

The HVAC guys I've all talked to recently (and it's been a few... sigh) all laugh at the Nest. Evidently 3M, Honeywell and whatnot have similar units for cheaper, although I think that depends how much you want the wifi (and not only wifi, but remote management) capabilities?

Although now for $249 the price premium ain't so bad, since high-end thermostats can easily get $300+... except I was going to settle for the $95 or the $105 one-- which also learn how long the system needs to reach the desired temperature for a lot less money than the nest.

Any idea how the Nest compares to other thermostats like the Honeywell RTH8500D?

The HVAC guys I've all talked to recently (and it's been a few... sigh) all laugh at the Nest. Evidently 3M, Honeywell and whatnot have similar units for cheaper, although I think that depends how much you want the wifi (and not only wifi, but remote management) capabilities?

Although now for $249 the price premium ain't so bad, since high-end thermostats can easily get $300+... except I was going to settle for the $95 or the $105 one-- which also learn how long the system needs to reach the desired temperature for a lot less money than the nest.

Any idea how the Nest compares to other thermostats like the Honeywell RTH8500D?

Here's the funny bit - Honeywell thermostats have been learning your a/c settings for the past decade. Only difference is they told no one how it works, as in, it's just a thermostat on a wall, who cares?

Oh, and "it just works." No BS firmware updates or other oddities that Nest does.

I have one, and I love it. Not only does it look great (if you think HAL 9000 looks great), but it's super easy to use.

I don't know whether it's worth $250, but I feel in the long run, it is.

The best thing about it is if I forget to turn it off before I leave, it will either go off automatically (learns), or I can just use the iPhone app. Similarly, when I am about to leave from work, I turn it on from my phone so my apartment is cool when I get back.

Quote:

Finally, can it be configured for a range of temperatures? Like during Spring and Fall, to not allow the temperature to go below 66F, but also not higher than 74F?

Yes, but there is a limited range, mostly so the temperatures in your house/apartment don't get out of hand.

Or you can get the radiothermostat (sold at Home Depot under the 3M filtrete name) for $99.

My year long experience is that the radiothermostat is works well and gets better with each new firmware, but apart from learning, it is wifi enabled, has windows and app support and is a hell of a lot cheaper than the nest.

Odd you didn't mention it considering it is $150 dollars less expensive.

HOWEVER both the Nest and the radiothermostat SUFFER from being only wifi enabled and controllable through apps. I actually prefer my older RF based thermostat with a remote control with an up and down clicker. It let me, in a dark bedroom, or from my desk, turn the AC or Heat on without having to look at a bright screen.

As an owner of two Nest devices I was surprised that this review doesn't mention two of its most useful features. Come on, Ars!

The first of which is that your Nest will email you monthly usage reports, comparing you against national averages. I was blown away the first time my thermostat emailed me to let me know how much energy I'd saved that month!

Next, for those who use the AC a lot, is a feature called "Airwave." Nest will, after it learns the heating/cooling patterns and timeframe for cooling a room, will automatically turn off your AC's compressor as it nears the desired temperature, keeping the blower on. This gives you another 10 minutes or so of "free" cool air, saving you even more money.

The Nest has definitely caught my attention, but I don't know if it would be suitable for my house. While I work a set schedule, my wife works the swing shift which alternates between nights and days every two weeks. We also have dual-zone heating/cooling so we would need 2 of them to cover the entire house. Anyways, I need to start my research and I am open to anything that is easy enough for my wife to use without getting frustrated.

The Nest has already saved me $250 and more in the last year compared to your traditional thermostat. It allows me to turn off my A/C remotely when I forget to (on trips, etc) and I can set up super-precise schedules to take advantage of the cool-off in the evenings.

I honestly can't see myself ever going back to a regular thermostat. The Nest is simple to use, beautiful, energy efficient, and adaptive.

I shopped around for a bit and went with Nest for the simplicity. Don't think the Honeywells and other high tech entries from the more traditional parties are lacking in any way, but I don't think my in-laws would be able to figure out what the fuck is going on with them. This thing is easy. Turn the dial, and done. In answer to others, there is a pretty robust intro video on the site that takes you through the " is this right for me?" questions, including wiring diagrams and so forth. I am FAR from a home repair guy and had no problems with installation. I can also state that the little screwdriver that comes with it is so /pretty/.

The only issue I had was that when I left for vacation I powered off most of my remote powered stuff, and realized from 2800 miles away that I had also powered off my Wifi network. So the in-law thing came in handy as my mother-in-law was able to turn it on before we got back to SoCal--the house was 90F. (our emergency turn on is 95F, which is when I figure stuff might start buckling.)

As an owner of two Nest devices I was surprised that this review doesn't mention two of its most useful features. Come on, Ars!

The first of which is that your Nest will email you monthly usage reports, comparing you against national averages. I was blown away the first time my thermostat emailed me to let me know how much energy I'd saved that month!

Next, for those who use the AC a lot, is a feature called "Airwave." Nest will, after it learns the heating/cooling patterns and timeframe for cooling a room, will automatically turn off your AC's compressor as it nears the desired temperature, keeping the blower on. This gives you another 10 minutes or so of "free" cool air, saving you even more money.

Also, if you're in a two (or more) zone household like I am, the Nest thermostats talk to each other and share their Away status and more.

I hate to break it to you, but that page is full of sht. The moment your compressor turns off, the cooling stops, period. End of story. 5-10 minutes is a flat out lie. Worse yet, running the fan afterwards just puts back into the air all the moisture on the coil, which took tremendous energy just to remove.

I find it also interesting that it won't do it if the humidity level is high, seeing how this thermostat didn't ever feature humidity control at all.

The first of which is that your Nest will email you monthly usage reports, comparing you against national averages. I was blown away the first time my thermostat emailed me to let me know how much energy I'd saved that month!

Also, if you're in a two (or more) zone household like I am, the Nest thermostats talk to each other and share their Away status and more.

I don't need dual zones, but I can appreciate a thermostat that has that. Also, I would love monthly/weekly usage reports comparing my usage to others in the same region -- I'd like to show that to my landlord as evidence the current A/C system is too small.

The HVAC guys I've all talked to recently (and it's been a few... sigh) all laugh at the Nest. Evidently 3M, Honeywell and whatnot have similar units for cheaper, although I think that depends how much you want the wifi (and not only wifi, but remote management) capabilities?

Although now for $249 the price premium ain't so bad, since high-end thermostats can easily get $300+... except I was going to settle for the $95 or the $105 one-- which also learn how long the system needs to reach the desired temperature for a lot less money than the nest.

Any idea how the Nest compares to other thermostats like the Honeywell RTH8500D?

Here's the funny bit - Honeywell thermostats have been learning your a/c settings for the past decade. Only difference is they told no one how it works, as in, it's just a thermostat on a wall, who cares?

Oh, and "it just works." No BS firmware updates or other oddities that Nest does.

I have a slightly older model of the honeywell 5-1-1 and cant begin to tell you how much it sucks. It was is tedious to program, and is totally worthless if you cant adhere to well defined routine. It has no ability to remotely change the temperature, which is what I want more than anything else.

I just installed a Nest. We have a 120-year old house in Cleveland that we did a deep energy retrofit on two years ago. (Energy geeks: it now rates HERS 38, whereas it started HERS 181). The thermostat we got, however, just never seemed to work right. I'm not sure I'll ever actually ever save the cost of the Nest, but I had some Amazon credits to blow.

Nevertheless, I like it so far. It is at least trying to save some energy in a house that is very efficient to begin with. It might succeed in a way I probably never could if I had to manually program a thermostat.

I do find it amazing, though, how ANGRY some people get about the mere existence of the Nest.

As an owner of two Nest devices I was surprised that this review doesn't mention two of its most useful features. Come on, Ars!

The first of which is that your Nest will email you monthly usage reports, comparing you against national averages. I was blown away the first time my thermostat emailed me to let me know how much energy I'd saved that month!

Next, for those who use the AC a lot, is a feature called "Airwave." Nest will, after it learns the heating/cooling patterns and timeframe for cooling a room, will automatically turn off your AC's compressor as it nears the desired temperature, keeping the blower on. This gives you another 10 minutes or so of "free" cool air, saving you even more money.

Also, if you're in a two (or more) zone household like I am, the Nest thermostats talk to each other and share their Away status and more.

I hate to break it to you, but that page is full of sht. The moment your compressor turns off, the cooling stops, period. End of story. 5-10 minutes is a flat out lie. Worse yet, running the fan afterwards just puts back into the air all the moisture on the coil, which took tremendous energy just to remove.

I find it also interesting that it won't do it if the humidity level is high, seeing how this thermostat didn't ever feature humidity control at all.

No. Most thermostats shut off the compressor and the fan at the same time. The coil is still cold. If you continue to blow air across it, you will continue to cool the house.

Mind you, you are correct about re-introducing moisture into the house if the humidity is high. That is why it doesn't activate that feature if the humidity is too high.

I just installed a Nest. We have a 120-year old house in Cleveland that we did a deep energy retrofit on two years ago. (Energy geeks: it now rates HERS 38, whereas it started HERS 181). The thermostat we got, however, just never seemed to work right. I'm not sure I'll ever actually ever save the cost of the Nest, but I had some Amazon credits to blow.

Nevertheless, I like it so far. It is at least trying to save some energy in a house that is very efficient to begin with. It might succeed in a way I probably never could if I had to manually program a thermostat.

I do find it amazing, though, how ANGRY some people get about the mere existence of the Nest.

The HVAC guys I've all talked to recently (and it's been a few... sigh) all laugh at the Nest. Evidently 3M, Honeywell and whatnot have similar units for cheaper, although I think that depends how much you want the wifi (and not only wifi, but remote management) capabilities?

Although now for $249 the price premium ain't so bad, since high-end thermostats can easily get $300+... except I was going to settle for the $95 or the $105 one-- which also learn how long the system needs to reach the desired temperature for a lot less money than the nest.

Any idea how the Nest compares to other thermostats like the Honeywell RTH8500D?

Here's the funny bit - Honeywell thermostats have been learning your a/c settings for the past decade. Only difference is they told no one how it works, as in, it's just a thermostat on a wall, who cares?

Oh, and "it just works." No BS firmware updates or other oddities that Nest does.

I have a slightly older model of the honeywell 5-1-1 and cant begin to tell you how much it sucks. It was is tedious to program, and is totally worthless if you cant adhere to well defined routine. It has no ability to remotely change the temperature, which is what I want more than anything else.

I just wish the Nest or the ecobee were cheaper.

Just so you know, the vast majority of today's systems take a mere 10% more energy to work in the heat of the day vs. night fall. All that heat that came in during the day will have to be removed sometime, and for most that still occurs while it is hot. Unless you are gone from like 9am to 8pm

A well installed and properly sized unit running the right airflow is much, much more important than the thermostat.

Quote:

I do find it amazing, though, how ANGRY some people get about the mere existence of the Nest.

That's because the nest sells on the assumption we all still use 8 SEER units from the 80s that were horribly inefficient and benefited most from programmable thermostats. That isn't the case.

Seems like a pretty good way of dealing with heating and cooling of a house, often the most energy intensive thing in a household. If there was some way to deal with me being home and not having the auto away kick in when i'm just in one part of the house versus the other I would consider it. Just the fact that it's brought awareness to the issue will get me to think and research thermostats when it comes up (something I never thought I would do).

As an owner of two Nest devices I was surprised that this review doesn't mention two of its most useful features. Come on, Ars!

The first of which is that your Nest will email you monthly usage reports, comparing you against national averages. I was blown away the first time my thermostat emailed me to let me know how much energy I'd saved that month!

Next, for those who use the AC a lot, is a feature called "Airwave." Nest will, after it learns the heating/cooling patterns and timeframe for cooling a room, will automatically turn off your AC's compressor as it nears the desired temperature, keeping the blower on. This gives you another 10 minutes or so of "free" cool air, saving you even more money.

Also, if you're in a two (or more) zone household like I am, the Nest thermostats talk to each other and share their Away status and more.

I hate to break it to you, but that page is full of sht. The moment your compressor turns off, the cooling stops, period. End of story. 5-10 minutes is a flat out lie. Worse yet, running the fan afterwards just puts back into the air all the moisture on the coil, which took tremendous energy just to remove.

I find it also interesting that it won't do it if the humidity level is high, seeing how this thermostat didn't ever feature humidity control at all.

No. Most thermostats shut off the compressor and the fan at the same time. The coil is still cold. If you continue to blow air across it, you will continue to cool the house.

Mind you, you are correct about re-introducing moisture into the house if the humidity is high. That is why it doesn't activate that feature if the humidity is too high.

That literally lasts no more than 10 seconds, not 5-10 minutes. I know this because I put my hand over the coil to see if the float switch cut off the system.

Thanks for the thoughtful review. I remain interested in the Nest, and I was pleasantly surprised when my old Cajun AC man said he was interested, too, but I really could use some numbers on savings: did you see any and what kinds of numbers? I know that this will vary depending upon location (environment) and usage, but it would help me to make a calculated decision: how long to see an ROI (return on investment)? Living in the deepest south, our electric bills can get pretty high in the six-month long summer we enjoy here in Louisiana, and so even a ten percent saving on a monthly summer bill could produce a quick ROI. (That's just an example: I don't really expect any thermostat to save 10% on energy costs.)

" Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen."

My neighbor once attempted to explain to me why I should leave my house at a constant temperature. You see, once the temperature falls, it takes extra energy to get it back up. It's kinda like a car, where cruising on the highway is more efficient than the acceleration and deceleration of city driving. :-D (^_^) ヅ ♬

The HVAC guys I've all talked to recently (and it's been a few... sigh) all laugh at the Nest. Evidently 3M, Honeywell and whatnot have similar units for cheaper, although I think that depends how much you want the wifi (and not only wifi, but remote management) capabilities?

Although now for $249 the price premium ain't so bad, since high-end thermostats can easily get $300+... except I was going to settle for the $95 or the $105 one-- which also learn how long the system needs to reach the desired temperature for a lot less money than the nest.

Any idea how the Nest compares to other thermostats like the Honeywell RTH8500D?

Here's the funny bit - Honeywell thermostats have been learning your a/c settings for the past decade. Only difference is they told no one how it works, as in, it's just a thermostat on a wall, who cares?

Oh, and "it just works." No BS firmware updates or other oddities that Nest does.

I have a slightly older model of the honeywell 5-1-1 and cant begin to tell you how much it sucks. It was is tedious to program, and is totally worthless if you cant adhere to well defined routine. It has no ability to remotely change the temperature, which is what I want more than anything else.

I just wish the Nest or the ecobee were cheaper.

Just so you know, the vast majority of today's systems take a mere 10% more energy to work in the heat of the day vs. night fall. All that heat that came in during the day will have to be removed sometime, and for most that still occurs while it is hot. Unless you are gone from like 9am to 8pm

A well installed and properly sized unit running the right airflow is much, much more important than the thermostat.

Quote:

I do find it amazing, though, how ANGRY some people get about the mere existence of the Nest.

That's because the nest sells on the assumption we all still use 8 SEER units from the 80s that were horribly inefficient and benefited most from programmable thermostats. That isn't the case.

A house built to todays building code will score HERS 100. A HERS 100 house would definitely benefit from a programmable thermostat. A programmable thermostat that never gets programed is useless, however. The Nest with its occupancy sensor to automatically set away mode makes it far more likely to get used.

My house (pre-renovation) was estimated at $8000/yr utilities (It was fire damaged when we bought it, so we couldn't really test that, but I have some indirect ways of confirming that). In its current state (HERS 38), it is under $2000/yr. HERS 100 would have at least doubled that, so a $250 thermostat could easily save its cost in energy in under a year. I have a big house, though, so those savings are magnified.

it's still a techie gadget. Completely useless and waste of money for anyone else. Even as a techie myself, I find this gadget to be a waste of money. It's not even a "nice to have"; more like, I have money I can spend, let's spend it on something, anything.

" Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen."

My neighbor once attempted to explain to me why I should leave my house at a constant temperature. You see, once the temperature falls, it takes extra energy to get it back up. It's kinda like a car, where cruising on the highway is more efficient than the acceleration and deceleration of city driving. :-D (^_^) ヅ ♬

That would require the a/c unit to run continuously. There are some that can do just that, and simply vary the capacity just like you vary the "gas" pedal

A house built to todays building code will score HERS 100. A HERS 100 house would definitely benefit from a programmable thermostat. A programmable thermostat that never gets programed is useless, however. The Nest with its occupancy sensor to automatically set away mode makes it far more likely to get used.

My house (pre-renovation) was estimated at $8000/yr utilities (It was fire damaged when we bought it, so we couldn't really test that, but I have some indirect ways of confirming that). In its current state (HERS 38), it is under $2000/yr. HERS 100 would have at least doubled that, so a $250 thermostat could easily save its cost in energy in under a year. I have a big house, though, so those savings are magnified.

Also: chill. It is just a thermostat.

And it benefits why???

Look, I've done actual power measurements of 1000s of systems from 730 in the morning to 8 at night. The vast majority of people save little to nothing by raising the temperature a few degrees.

A house built to todays building code will score HERS 100. A HERS 100 house would definitely benefit from a programmable thermostat. A programmable thermostat that never gets programed is useless, however. The Nest with its occupancy sensor to automatically set away mode makes it far more likely to get used.

My house (pre-renovation) was estimated at $8000/yr utilities (It was fire damaged when we bought it, so we couldn't really test that, but I have some indirect ways of confirming that). In its current state (HERS 38), it is under $2000/yr. HERS 100 would have at least doubled that, so a $250 thermostat could easily save its cost in energy in under a year. I have a big house, though, so those savings are magnified.

Also: chill. It is just a thermostat.

And it benefits why???

Look, I've done actual power measurements of 1000s of systems from 730 in the morning to 8 at night. The vast majority of people save little to nothing by raising the temperature a few degrees.

If you are only talking about AC, maybe. What climate are you in? In Cleveland, you can save some serious coin by reducing the temperature you heat the house to while you are away.

At the price point the device is a complete fail for a modern HVAC system. Only one cooling mode and two heating for staged systems, especially with newer HVAC systems moving to multiple heating and cooling stages.

Multiple zone support looks better until you realize you need a separate Nest thermostat for each zone and that central coordination is marginal at best. Each unit operates entirely on it's own for creating auto-away schedules.

Both of the above technologies are cornerstones for modern high efficiency HVAC systems and will save you a lot more than an auto-away feature, since just about any coordinated multistage, multizone system already has similar features and timers integrated. Great systems integrate with security and / or motion sensors and thermostats throughout the house to figure out when and where people are in the home. They also have iOS, Android, and web applications and alerts.

The review should have said it simply: A simple device for retrofitting timer use on old HVAC systems without having to read the manual to set timers. A great hipster home accessory and conversation piece.

A house built to todays building code will score HERS 100. A HERS 100 house would definitely benefit from a programmable thermostat. A programmable thermostat that never gets programed is useless, however. The Nest with its occupancy sensor to automatically set away mode makes it far more likely to get used.

My house (pre-renovation) was estimated at $8000/yr utilities (It was fire damaged when we bought it, so we couldn't really test that, but I have some indirect ways of confirming that). In its current state (HERS 38), it is under $2000/yr. HERS 100 would have at least doubled that, so a $250 thermostat could easily save its cost in energy in under a year. I have a big house, though, so those savings are magnified.

Also: chill. It is just a thermostat.

And it benefits why???

Look, I've done actual power measurements of 1000s of systems from 730 in the morning to 8 at night. The vast majority of people save little to nothing by raising the temperature a few degrees.

If you are only talking about AC, maybe. What climate are you in? In Cleveland, you can save some serious coin by reducing the temperature you heat the house to while you are away.

I'm in FL.

Heating is a different story since instead of there being a typical temp differential of 20-30 degrees, it can be 60-80. Instead of say having the heat at 70 while you are home, you may have it as low as 55, which for a lot of people is better than the 10 degrees or lower outside when they return.

Here I tell people to start heating around sunset because heat is abundant to move inside via their heat pump.

" Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen."

My neighbor once attempted to explain to me why I should leave my house at a constant temperature. You see, once the temperature falls, it takes extra energy to get it back up. It's kinda like a car, where cruising on the highway is more efficient than the acceleration and deceleration of city driving. :-D (^_^) ヅ ♬

That would require the a/c unit to run continuously. There are some that can do just that, and simply vary the capacity just like you vary the "gas" pedal

I'm talking about heating, but i don't think it matters. I live in the northeast where, for me at least the job of a thermostat when I am not home us to keep the pipes from bursting. :-) my house was built in 1900 with radiators and a gas-fired boiler. We aren't talking about a few degrees.

All other things being constant, for a given home, the rate of heat loss is proportional to the temperature differential between inside and outside. If you're "continuous flow" ac saves energy over simply shutting it off, it is from some other implementation detail of the ac unit.

I don't understand why you're complaining about the Nest app, just go to the website, the iPhone is more than capable of rendering it I would assume? Why even use the app for the rare times you really have to interrupt your day to check on your house? Seems just like another meaningless task people will assign themselves to make them feel busy when really it's not that important, don't sweat the small stuff as they say, you'll feel less stressed

And how often do you want to check in to your home thermostat? My old school $19.99 one lets me set the date and time I want to change the temperature, and has a vacation setting....so I'm not sure why you would pay $250 or more unless your time is worth more than the ten minutes it takes to read the manual and set it?

" Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen."

My neighbor once attempted to explain to me why I should leave my house at a constant temperature. You see, once the temperature falls, it takes extra energy to get it back up. It's kinda like a car, where cruising on the highway is more efficient than the acceleration and deceleration of city driving. :-D (^_^) ヅ ♬

That would require the a/c unit to run continuously. There are some that can do just that, and simply vary the capacity just like you vary the "gas" pedal

I'm talking about heating, but i don't think it matters. I live in the northeast where, for me at least the job of a thermostat when I am not home us to keep the pipes from bursting. :-) my house was built in 1900 with radiators and a gas-fired boiler. We aren't talking about a few degrees.

All other things being constant, for a given home, the rate of heat loss is proportional to the temperature differential between inside and outside. If you're "continuous flow" ac saves energy over simply shutting it off, it is from some other implementation detail of the ac unit.

There you got the idea. Those units I'm talking about, one of them, the Mitsubishi Hi2Heat heat pump series can heat down to -18 degrees F. 80% of capacity is still at 5, or maybe -11.

I don't understand why you're complaining about the Nest app, just go to the website, the iPhone is more than capable of rendering it I would assume? Why even use the app for the rare times you really have to interrupt your day to check on your house? Seems just like another meaningless task people will assign themselves to make them feel busy when really it's not that important, don't sweat the small stuff as they say, you'll feel less stressed

And how often do you want to check in to your home thermostat? My old school $19.99 one lets me set the date and time I want to change the temperature, and has a vacation setting....so I'm not sure why you would pay $250 or more unless your time is worth more than the ten minutes it takes to read the manual and set it?

I cannot adhere to a schedule. Some days I get home at 5, other days I get home at midnight. It doesn't matter how assiduously I program my my $70 honeywell unit, it either turns on too early and wastes energy or I come home and my house is 55 degrees. I want to be able to set my home temp about one hour before I come home, when I am at the office etc.